A known electronic device includes a printed circuit board, a component that generates heat (heat-generating component), and a casing that houses the printed circuit board and the heat-generating component. Examples of such an electronic device are disclosed in Japanese Laid-open Patent Publications Nos. 09-258849 and 62-257786.
In an electronic device, the heat of the heat-generating component is transmitted to the printed circuit board, if the printed circuit board and the heat-generating component are arranged close to each other. When traveling along the printed circuit board in a certain direction, the heat may reach a part that resists heat dissipation. In this case, the temperature of the printed circuit board may increase. Further, the temperature of the interior of the casing may also increase.